*{
	margin: 0;
	padding: 0;
}
header{
	width: 1366px;
	height: 100px;
}
nav{
	width: 800px;
	height: 40px;
	background-color: #eee;
	margin: 0 auto;
}
nav ul{
	list-style: none;
}
ul li{
	float: left;
	line-height: 40px;
	text-align: center;
	position: relative;
}
ul li a{
	padding: 0 20px;
	text-decoration: none;
	display: block;
}
a:hover{color:#FFF;background-color: #666;}
ul li ul{
	position: absolute;
	left: 0px;
	top:40px;
	display: none;
}
ul li:hover ul{display: block;}
ul li ul li{
	float:none;
	background-color: #eee;
	margin-top: 2px;
}
ul li ul li a:hover{background-color: blue}
